CVE-2015-8791

The EbmlElement::ReadCodedSizeValue function in libEBML before 1.3.3 allows context-dependent attackers to obtain sensitive information from process heap memory via a crafted length value in an EBML id, which triggers an invalid memory access.

Published: 2016-01-29 Last update: 2026-05-06 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2015-8791 is rated Moderate Risk (41.8/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.34%). EPSS rose +1.00% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2015-8791

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.34% 1.34% +1.00%
2 2025-07-07 0.44% 0.34% -0.10%
3 2025-03-30 — 0.44% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2015-8791

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 3.0 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 1.4 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2015-8791

OS Trackers for CVE-2015-8791

vendor priority summary link
debian not yet assigned CVE-2015-8791 not yet assigned priority: Debian including 1 source packages (libebml), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2015-8791
ubuntu medium CVE-2015-8791 medium priority: Ubuntu including 1 source packages (libebml), 6 status rows across 6 suites (precise, trusty, upstream, vivid, wily, xenial): released 3, ignored 2, not-affected 1. https://ubuntu.com/security/CVE-2015-8791

Affected software / configurations for CVE-2015-8791

Vendor Product Version Raw CPE
matroska libebml <= 1.3.2 cpe:2.3:a:matroska:libebml:*:*:*:*:*:*:*:*

References for CVE-2015-8791

cvelogic Threat Intelligence